1. The Field of the Invention
This invention relates to ladder accessories and, more particularly, to a wall stand-off apparatus for supporting and stabilizing a ladder adjacent a substantially vertical surface.
2. The Prior Art
Ladders have been used by nearly everyone to perform some kind of construction or repair task. For example, ladders are frequently used when painting or wallpapering a room or when framing or finishing a new structure.
Despite the wide use of ladders, however, a significant number of household and construction accidents occur each year which are related to ladder use. Of course, some of these accidents result from the negligence of the individual using the ladder, and other accidents can perhaps be traced to faulty ladder design or construction. However, there are several situations in which the use of a ladder remains awkward and/or dangerous in spite of the fact that the ladder is well-designed and constructed and that the user is reasonably careful during its use.
One such situation arises when it is necessary to work at or near the top of a ladder which is leaning against a vertical support. For example, when working on the outside of a house, the edges of the roof generally hang over the outside vertical walls, thereby making it awkward to work near the top of a ladder which lies directly below the roof. Working under other types of overhangs may similarly make ladder work difficult. Unfortunately, in such a situation the user often finds himself standing very close to the top of the ladder with nothing to hang onto. He may also be required to attempt some awkward and dangerous reaching in order to accomplish his desired objective. These factors, of course, may contribute significantly to the danger of ladder use.
Another common situation in which proper ladder use may be awkward arises when a ladder must be used adjacent windows and shrubs. As a general rule, the base of a ladder should be positioned one foot away from the ladder's vertical supporting surface for every four feet of ladder length. However, when working adjacent windows and shrubs, it is frequently difficult to maintain this proper slope. Often, for example, if the ladder were to be positioned properly, the top of the ladder would rest against a window; consequently, in order to avoid damaging the window, the ladder user either positions the top of the ladder just below or above the window. Thus, the user may find that the ladder is improperly positioned to support him. Similar problems may arise when a ladder must be used adjacent shrubs, since the proper positioning of the base of the ladder may be impossible.
A further situation which may make ladder use awkward or dangerous occurs when a ladder must be used adjacent an uneven vertical surface. Occasionally, an individual will simply place a ladder against an uneven surface and then attempt to climb the ladder, even though only one of the ladder's side rails is actually in contact with the vertical supporting surface. It will be readily appreciated that this situation creates a substantial danger, and a ladder so positioned will frequently twist away from the supporting surface and fall.
The inherent danger of ladder usage is also increased when a ladder is used on very tall jobs or in connection with heavy loads. In such cases, the ladder may bow, or even collapse, in the middle; and the ladder may also twist during use, thereby causing both the ladder and its user to fall.
In order to minimize the awkwardness and danger involved in each of the above-mentioned situations, those skilled in the art have commonly used a device called a wall stand-off. As illustrated in FIG. 7, a typical prior art stand-off comprises two support arms 110 which are connected to the side rails 92 of a ladder 90 by means of bolts 112. By using this device, one may easily work adjacent the top of the ladder while still having sufficient room to hang onto the top of the ladder's side rails. Additionally, since the ladder is supported a predetermined distance from the supporting wall, awkward and dangerous reaching can be minimized. It will further be appreciated that this prior art stand-off can be positioned such that the proper ladder slope is maintained when the ladder is used adjacent windows or shrubs. Also, by making one of the support arms longer than the other, the stand-off can facilitate ladder usage against uneven vertical surfaces. Finally, the prior art stand-off could also be positioned adjacent a central portion of the ladder in order to provide additional support when the ladder is used with heavy loads.
However, in spite of the advantages of the prior art type of wall stand-off there are several disadvantages associated with its use. First, it will be appreciated that since the stand-off's arms 110 are bolted to the side rails 92 of the ladder 90, the stand-off is somewhat inconvenient to remove. Significantly, a worker often finds himself without the correct tools to remove the standoff. Consequently, when using a ladder to which a stand-off has been attached, a worker may try to use the ladder without removing the stand-off. There are numerous situations in which the use of a stand-off would not be appropriate and would tend to increase the danger of ladder usage.
Additionally, the prior art type stand-off is somewhat burdensome to attach to a ladder. Typically, both the stand-off's support arms and the ladder's side rails must be drilled or otherwise provided with appropriate holes to receive the bolts. Thus, if it later becomes desirable to use the stand-off at a different position along the length of the ladder's side rails, the side rails would have to be re-drilled at the appropriate location. In addition to being inconvenient, frequent drilling may, of course, weaken the ladder and precipitate ladder failure. Additionally, since the prior art stand-offs are typically not mass produced, a stand-off may rarely be used on more than one ladder. Further, the prior art stand-off's support arms are not readily adjustable in length; thus, it is difficult to use the prior art stand-off against an uneven vertical surface.